Say positive things at every opportunity. Say thank you; give praise, pay compliments.
Focus on your strengths and write three affirmations that begin “I am…” They needn’t be true (yet).
Monitor your speech over a day. Note the patterns you fall into and start rephrasing. Try some simple switches I’m hopeless at… I’m learning to It’s impossible… It’s a real challenge No problem... You’re welcome I messed up… I can do better I’m stressed… I have a lot on